1. Field of the Invention
The disclosed information relates to an ink jet recording apparatus, which discharges ink from a recording head to perform recording on a recording medium, and to an ink jet recording method therefor. The disclosed information particularly relates to an ink jet recording apparatus for two-sided recording on a recording medium, and to an ink jet recording method therefor.
2. Description of the Related Art
Generally known recording apparatuses applied to printers, copying machines, and facsimiles record an image formed of dot patterns on a recording medium such as paper and a plastic thin plate based on recording information. Methods for recording an image formed of dot patterns include the ink jet method, wire dot method, thermal method, and laser beam method. Among these, the ink jet method discharges ink drops (recording liquid) from a discharge port of a recording head to the recording medium, and then fixes the ink thereon. This method has a benefit of a comparatively low price.
The ink jet method has a problem of the occurrence of stain, called smear, and other image failures. Since the ink jet method uses ink composed of waterborne liquid, it is necessary to volatilize moisture contained therein. Specifically, the ink jet method requires a time duration necessary for ink to dry and for the recorded image to fix (hereinafter, referred to as ink drying time).
However, when a second recording medium is discharged and placed onto a previously discharged, first recording medium having ink that has not fully dried (hereinafter, referred to as semi-dry ink) thereon, ink from the first recording medium may adhere to the rear surface of the just discharged second recording medium. In this case, the rear surface of the subsequently discharged, second recording medium will degrade the image recorded on the previously discharged, first recording medium, causing smear on the rear surface of the second recording medium. When a recording area has a high recording ratio, a large ink discharge amount prolongs the ink drying time and makes smear more likely to occur.
With an ink jet recording apparatus that performs two-sided recording on a recording medium, a secondary smear may occur. With such an ink jet recording apparatus having the two-sided recording function, recording is made on a first surface of the recording medium and then the recording medium is fed to a reversing conveyance path. Then, the recording medium is reversed and then recording is made on the other, second surface.
In this case, when the recording medium is fed to the reversing conveyance path before ink has fully dried, semi-dry ink grazes in the reversing conveyance path, resulting in degraded image or smear. In addition to smear, secondary smear occurs. Specifically, ink adhering to the conveyance path stains the following recording medium passing therethrough.
Japanese Patent Application Laid-Open No. 2005-125750 discusses a technique that attempts to address this. The technique includes dividing an area corresponding to one surface of a recording medium into multiple areas, setting an ink drying time according to the amount of ink to be discharged to each unit area, and performing recording on one surface (front surface) of the recording medium. After the ink drying time has elapsed, the recording medium is fed to the reversing conveyance path and recording is performed on the other surface (rear surface) of the recording medium.
However, when performing two-sided recording with the technique discussed in Japanese Patent Application Laid-Open No. 2005-125750 in a situation where there exists a high-duty area having a large ink discharge amount on the surface previously recorded, it is necessary to set an ink drying time that is long enough to prevent smear, even when the recording medium is fed again to the reversing conveyance path. Therefore, this technique has a problem that two-sided recording takes additional time.